a. Field of Invention
The invention relates generally to transradial catheterization methods and devices used in said methods. In particular the invention concerns a method of obtaining patent hemostasis of the radial artery by compressing the un-instrumented ulnar artery to increase radial artery flow while applying pressure to the radial artery access site. The invention further concerns a device for applying blunt pressure to the ulnar artery, and a method of use.
b. Description of Related Art
Radial artery instrumentation is becoming increasingly prevalent with cardiovascular procedures performed via transradial access, providing improvement in outcomes, cost, as well as comfort. Radial artery occlusion refers to the blockage of the radial artery. Radial artery occlusion is a consequence of radial artery cannulation, which obliterates the radial artery lumen, making it not available for access in the future.
After instrumentation, it is necessary to compress the radial artery at the access site to obtain hemostasis of the cannulation wound. The cannulation wound is an opening of the wall of the radial artery. Hemostasis of the cannulation (or sheath) wound is accomplished by applying blunt pressure to the radial artery at the cannulation wound site, or access site. The application of this blunt pressure on the radial artery often causes the artery to occlude or close, thereby denying bloodflow further downstream within the radial artery. Maintaining blood flow in the radial artery while compressing the access site, after instrumentation, reduces the risk of post-instrumentation radial artery occlusion. Patent hemostasis is therefore understood to mean achieving the cessation of bleeding at the cannulation wound (access site) of the radial artery, while blood is allowed to flow through the artery.
The following references are representative of the field pertaining to the present invention:
For example, U.S. Pat. No. 6,355,026 to Mick describes right and left coronary catheters that are designed to be used in a transradial coronary catheterization. Also discussed are methods of inserting the catheters into a right or left coronary artery by a transradial approach.
In an article entitled Efficacy and Safety of Transient Ulnar Artery Compression to Recanalize Acute Radial Artery Occlusion After Transradial Catheterization (Am J Cardiol 2011;107:1698-1701) Ivo Bernat, MD, and others, discuss a method directed to open an occluded radial artery after the radial artery becomes occluded. In the case of radial artery occlusion, 3-4 hours after hemostasis of the radial artery, ulnar artery compression was applied to attempt recanalization of radial artery. Bernat et. al. verified reopening of the radial artery by administration of heparin and compression of the ulnar artery.
Transradial access is being increasingly used because of its ability to reduce access-site complications and increase patient comfort. While performing transradial catheterization, upon introduction of the introducer sheath or catheter into the radial artery, it is best practice to administer anticoagulant, e.g., unfractionated heparin, bivalirudin or Enoxaparin, to assist in the prevention of radial artery occlusion, even when the catheterization procedure itself would otherwise not require it. Anticoagulants may also be referred to as blood thinners. The prophylactic effect of an anticoagulant such as unfractionated heparin to reduce the occurrence of radial artery occlusion is dose-dependent with significantly better efficacy with higher doses. With the administration of 5000 units of unfractionated heparin or alternatively 50 units per kilogram (kg) of body weight, radial artery occlusion rates have been reported in the range of 4-5%. Doses of heparin to be administered are generally expressed in units of heparin per kg of body weight. A conventional dose of unfractionated heparin during a transradial catheterization procedure is about 50 units per kg of body weight. A conventional dose of other anticoagulants, such as Bivalirudin or Enoxaparin is the equivalent of 50 units of unfractionated heparin per kg of body weight.
In view of the anticoagulant effect of unfractionated heparin, which effect typically exceeds the duration of the cardiovascular procedure, the patient is systemically anticoagulated with observed activated clotting times of approximately 200-225 seconds, while undergoing hemostasis. Optimally, a minimum duration of about 120 minutes of compression at the radial artery access site is required to achieve hemostasis.